Figure 2.

The frequency of TIDA neuron Ca²⁺ oscillations increases during lactation. A, Representative concomitant traces of Ca²⁺ fluctuations in DAT-GCaMP3 neurons in the dmArc from the same slice in adult males (Aa), female in diestrus/metestrus (D/M; Ab), female in estrus (from the proestrus+estrus group; P + E; Ac), and lactating dam (Ad). B, Box plot represents the frequency of the Ca²⁺ oscillations in DAT-CGaMP3 neurons in the dmArc recorded from female mice in proestrus and estrus. There is no significant difference between the two groups (unpaired Student's t test, p = 0.14). n indicates the number of animals/neurons. Box plots represent the interquartile ranges (square) and median (line). Values with whiskers indicate minimum and maximum values. C, Scatter plots represent the mean frequency and SEM of oscillating DAT-GCaMP3 neurons in the dmArc (i.e., all oscillating cells, from all slices of a single mouse). The mean frequency was significantly different between the lactating group and the male, D/M, and P + E groups. ***p< 0.001 (one-way ANOVA with Tukey's multiple comparison as post hoc test). **p > 0.01 (one-way ANOVA with Tukey's multiple comparison as post hoc test). All other comparisons between groups are nonsignificant. n indicates the number of animals/cells. D, The number of oscillating cells in a slice plotted against the mean oscillation frequency of the same slice. No correlation (Pearson correlation: R² < 0.05) is found, suggesting that the number of active cells within a preparation does not influence the speed of the activity. E, Serum prolactin concentration measured by immunoassay in the experimental groups shown in C. *p > 0.05 (one-way ANOVA with Tukey's multiple comparison as post hoc test). **p > 0.01 (one-way ANOVA with Tukey's multiple comparison as post hoc test). All other comparisons between groups are nonsignificant. n indicates the number of samples/animals.